Doc: Replace the deprecated highlightlang directive by highlight. (#13377)

highlightlang is deprecated since April 2018 in Sphinx.
See https://github.com/sphinx-doc/sphinx/pull/4845
diff --git a/Doc/faq/windows.rst b/Doc/faq/windows.rst
index ad97cd0..a181086 100644
--- a/Doc/faq/windows.rst
+++ b/Doc/faq/windows.rst
@@ -1,6 +1,6 @@
 :tocdepth: 2
 
-.. highlightlang:: none
+.. highlight:: none
 
 .. _windows-faq: